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From: Anthony Jenkins <abjenkins@mindspring.com>
Subject: Runtime object type determination/ runtime generic instantiation
Date: 1997/11/06
Message-ID: <34626166.D12266B@mindspring.com>#1/1
X-Deja-AN: 287529631
X-Server-Date: 7 Nov 1997 00:32:51 GMT
Organization: MindSpring Enterprises
Newsgroups: comp.lang.ada
Date: 1997-11-07T00:32:51+00:00
List-Id: <comp.lang.ada>


I'm having to instantiate a generic package which can use any private
type (equality/assignment methods defined) for a type specified in a
file.  e.g. the string "character" would be read from a file and I'd
have to use my package instantiated for the type 'character'.

If runtime generic instantiation were possible I could avoid
instantiating the package for every single non-limited type there is,
and if runtime object type determination were possible I was thinking I
could determine how to handle the type in the package body at runtime
(since strings I believe are non-limited and differ substantially from
scalar non-limited types in their handling).

The package I have to create is one for (un)directed graphs, where the
vertices can represent numbers, characters or strings (I'm thinking more
generically than these 3 types so I can possibly use it later) where the
node value type is given in a file.  Am I looking at this wrong?  I'm
seeing a huge (well, 3-clause) CASE statement (after instantiating each
of 3 different graph packages) that calls whatever operations are
available from the package using that type.  Anyway, thanks in advance
for any pointers.


Anthony Jenkins
http://www.auburn.edu/~jenkian
abjenkins @ mindspring , com (Death to spammers)

-------------
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